Point-of-care testing includes medical testing at or near the site of patient care, such as at a doctor's office or on-site patient testing lab. A significant advantage of point-of-care testing is that tests (e.g., blood tests, etc.) can be performed quickly and locally such that test results may be obtained and reviewed while a patient is present on site. Such point-of-care testing can eliminate the need for sending samples to an off-site laboratory, which typically involves delayed receipt of testing results, which can delay clinical management decisions.
While POCT systems can offer significant benefits in terms of convenience and rapidly available test results, in order to provide meaningful information, these systems need to produce accurate and reliable test results. Rapidly available on-site test results may be convenient, but they may have little clinical value if they are error prone or if they experience significant variation from measurement to measurement. POCT systems often rely upon the use of disposable elements for capturing and retaining a sample for analysis. Such disposables can vary from one another and can introduce imprecision into the system, as a different disposable may be introduced for each new measurement. Thus, there is a need for POCT units capable of adapting to the variations introduced into the measurement system and analysis through interaction with disposable elements.
Some POCT systems may involve optical testing and may include optics that can be focused in order to improve the signal to noise ratio of optical measurements. With variations in disposable units (e.g., introduced through manufacturing variations, variation in placement of the disposable within the analysis system, etc.), the optics in a POCT system may require focusing each time a different disposable is introduced into the system, or even during some types of measurements. In some cases, focusing mechanisms may include highly accurate stepper or actuator systems (e.g., piezoelectric-based systems). While these systems may offer the desired accuracy, they can introduce added expense and complexity into the system.